This invention relates to an image formation system such as an electrophotographic color copier or a color laser-beam printer and in particular to an image formation system making the effective use of the space therein.
To place parts required for the image formation operation, such as a fuser and units for feeding and transporting recording sheets in a paper feed tray, in an image formation system, it is necessary to make it possible to miniaturize the image formation system making the effective use of space and facilitate maintenance of the image formation system.
To miniaturize the image formation system, the parts such as the fuser and the paper feed and transport units need to be placed with good space efficiency within the limited volume range of the image formation system.
The following related art (J01) is known as an art for placing the parts so as not to waste space in an image formation system:
(J01) (art described in the Unexamined Japanese Patent Application Publication No. Hei 5-338832) PA1 (J02) (art described in the Unexamined Japanese Patent Application Publication No. Hei 6-138744) PA1 (J03) (art described in the Unexamined Japanese Patent Application Publication No. Hei 7-199678) PA1 an image support having a rotating surface for supporting a toner image thereon; PA1 a developing unit being disposed adjacent to the image support for forming a toner image on the surface of the image support; PA1 an intermediate transfer body being disposed adjacent to the image support, to which the toner image formed by the developing unit is transferred; PA1 a primary transfer device for transferring the toner image from the image support to the intermediate transfer body; PA1 a second transfer device for transferring the toner image transferred from the image support to the intermediate transfer body to a recording sheet; PA1 a thermal fuser being disposed below the developing unit and on a side of the secondary transfer device for thermally fixing the toner image transferred to the recording sheet by the secondary transfer device on the recording sheet; and PA1 heat insulation means being disposed between the thermal fuser and the developing unit for preventing heat generated from the thermal fuser from being transmitted to the developing unit. PA1 an image support having a rotating surface for supporting a visible image thereon; PA1 a developing unit being disposed adjacent to the image support for forming a visible image on the surface of the image support; PA1 an intermediate transfer body being disposed adjacent to the image support, to which the visible image formed by the developing unit is transferred; PA1 a primary transfer device for transferring the visible image from the image support to the intermediate transfer body; PA1 a secondary transfer device for transferring the visible image transferred from the image support to the intermediate transfer body to a recording sheet; PA1 a fuser being disposed below the developing unit and on a side of the secondary transfer device for fixing the visible image transferred to the recording sheet by the secondary transfer device on the recording sheet; PA1 a sheet tray being disposed below the secondary transfer device and the fuser for storing recording sheets on which images are formed; and PA1 a top stage sheet tray being shorter than the sheet tray with respect to a paper feed direction and disposed at a position below the secondary transfer device and not overlapping the thermal fuser with respect to an up and down direction.
FIG. 5 is a schematic representation of the art described in the Unexamined Japanese Patent Application Publication No. Hei 5-338832.
The apparatus illustrated in FIG. 5 includes paper feed trays 02a and 02b below image support 01. The paper feed tray 02a is located above paper feed tray 02b and has a length which is approximately one-half the length of paper feed tray 02b.
The non-paper feed end parts (left end parts in the figure) opposite to the paper feed side end parts (right end parts in the figure) of the smaller paper feed tray 02a and the normal paper feed trays 02b are placed so as to overlap each other up and down. Therefore, a space Sg is formed on the paper feed side of the small paper feed tray 02a.
Sheet passages 03a and 03b are connected to the paper feed side end parts of the small paper feed tray 02a and the normal paper feed tray 02b respectively, and the sheet passage 03b to the normal paper feed tray 02b connects to a merging passage 04.
The sheet passage 03a to the paper feed tray 02a at the top stage is bent and connects to the merging passage 04 and a sheet transport passage 07 at a merging point 06 in the space Sg.
A recording sheet (not shown) sent out from the small paper feed tray 02a at the top stage in the arrow direction shown in FIG. 5 is transported on the sheet passage 03a through the merging point 06 to the sheet transport passage 07.
the merging point 06 is placed in the space Sg on the paper feed side of the small paper feed tray 02a, whereby if paper feed trays are placed at multiple stages as much as possible within the limited volume range of the image formation system, the curvature radius of the bent part of the sheet passage 03a to the paper feed tray 02a connecting to the merging part 06 can be enlarged and when a card with large friction, a firm film, etc., passes through along the sheet passage 03a, a jam, etc., is prevented from occurring.
The following related art (J02) is known as an art devising placement of the parts of an image formation system for miniaturizing the image formation system and facilitating maintenance thereof:
In this art described here, a plurality of color developing units are placed vertically in overlapped relation below an intermediate transfer belt placed in an image formation system and a belt-like image support opposed to the developing units and vertically extending is placed. The effective use of space in the image formation system is made because of the placement, etc., for making the image formation system compact and facilitating maintenance thereof.
The following related art (J03) is known as an art for placing the parts of an image formation system laying emphasis on easy maintenance of the parts in the image formation system:
In this art described here, an intermediate transfer body unit for holding an intermediate transfer body is placed detachably in an image formation system. An intermediate transfer body cleaning device for collecting residue toner on the intermediate transfer body is placed detachably in the intermediate transfer body unit. At the maintenance time, if the intermediate transfer body unit is drawn out from the image formation system, the intermediate transfer body cleaning device is also drawn out together, saving trouble to adjust the contact position between the intermediate transfer body cleaning device and the intermediate transfer body after the termination of the maintenance.